Thank crivens for Roxana Torres and colleagues, of the Institute of Ecology at Universidad Nacional Autónoma de Mexico, and their paper: “Senescent birds redouble reproductive effort when ill: confirmation of the terminal investment hypothesis,” published today in Proceedings of the Royal Society B.

The terminal investment hypothesis is a pretty intuitive idea and should be the same for all long-lived species. Simply put if you know you are not long for this Earth then the trade-off between everyday survival and reproductive effort tips in favour of getting one's end away.

Although the hypothesis was proposed way back in 1966, before this new study in birds, evidence to support it had so far been scant.

The team took two groups of male blue-footed boobies, one in their studly prime and one, relatively speaking, peck-peck-peckin' on heaven's door. Both were injected with a bacterial toxin. This elicited an immune response much the same as being diagnosed with a bout of the flu (not bird flu); if you're close to full-time coffin-dodging then your number could easily be up.

The plucky old boobies then redoubled their reproductive efforts, showing a 98 per cent increase in luck with the birds, in the form of more fledglings. The younger group's success meanwhile fell away in response to the immune stress.

The implications here are obvious - old folks just can't help themselves.

In conclusion, the recent spate of superannuated lustiness is nothing new, its evolutionarily hard-wired; birds do it, bees do it, continental OAPs do it. As an Australian toad hunter might say: “Not in my backyard.”®

Bootnote

Expect the inhumanity to get worse. As we reported, fiftysomethings are already being rather inappropriate.